a4j:mediaOutput allows to generate images, video, sounds and other binary
resources defined by a user on-the-fly.

createContent attribute references to the managed Bean method that will be used
for content creating. The method accepts two parameters. The first parameter
has an OutputStream type. It is a reference to the steam that should be used for output.
The second parameter is a reference to a 'value' attribute of the component.

value attribute references to some managed Bean with data that can be
used as input data for a content
creator method. The object should be serializable because it is encoded to the URL
of the resource.

mimeType attribute defines the type of output content. It is used to define
the corresponded type in the header of an HTTP response.

cacheable attribute is a flag that defines the caching strategy. If 'cacheable'
is set to false, the response will not be cached. If it is set to true, it will be cached
and the serialized value of 'value' attribute plays the role of a cache key.

Note for SWF sample. Using scripts loading strategy different from "ALL" you should use additionally load swfObject script by using:
<a4j:loadScript src="resource:///org/richfaces/renderkit/html/js/swfobject.js" />